U.S. patent application number 12/805372 was filed with the patent office on 2010-11-18 for method for manufacturing printed circuit board.
This patent application is currently assigned to SAMSUNG ELECTRO-MECHANICS CO., LTD.. Invention is credited to Keun-Ho Kim, Eung-Suek Lee, Dek-Gin Yang.
Application Number | 20100288726 12/805372 |
Document ID | / |
Family ID | 38992497 |
Filed Date | 2010-11-18 |
United States Patent
Application |
20100288726 |
Kind Code |
A1 |
Lee; Eung-Suek ; et
al. |
November 18, 2010 |
Method for manufacturing printed circuit board
Abstract
A method of manufacturing a printed circuit board including:
forming a heat dissipating coating layer on the surface of a heat
dissipating layer; forming circuit patterns on the surface of an
insulating layer, and forming an inter-layer conductive part
joining with the insulating layer by passing through the insulating
layer and electrically connected with the circuit patterns; and
laminating the insulating layer on the heat dissipating layer such
that the inter-layer conductive part is connected with the heat
dissipating coating layer.
Inventors: |
Lee; Eung-Suek; (Ansan-si,
KR) ; Yang; Dek-Gin; (Cheongwon-gun, KR) ;
Kim; Keun-Ho; (Daejeon, KR) |
Correspondence
Address: |
STAAS & HALSEY LLP
SUITE 700, 1201 NEW YORK AVENUE, N.W.
WASHINGTON
DC
20005
US
|
Assignee: |
SAMSUNG ELECTRO-MECHANICS CO.,
LTD.
Suwon
KR
|
Family ID: |
38992497 |
Appl. No.: |
12/805372 |
Filed: |
July 27, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11812661 |
Jun 20, 2007 |
|
|
|
12805372 |
|
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Current U.S.
Class: |
216/20 ;
156/278 |
Current CPC
Class: |
H05K 3/4647 20130101;
H05K 2201/0323 20130101; H05K 2201/096 20130101; H05K 1/0207
20130101; H05K 3/4614 20130101; H05K 1/0206 20130101; H05K 3/4641
20130101; H05K 3/4652 20130101; H05K 2203/1189 20130101; Y10T
29/49155 20150115; H05K 1/056 20130101; H05K 3/4069 20130101 |
Class at
Publication: |
216/20 ;
156/278 |
International
Class: |
H01B 13/00 20060101
H01B013/00; B32B 37/00 20060101 B32B037/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 21, 2007 |
KR |
10-2006-0055844 |
Claims
1. A method of manufacturing a printed circuit board, the method
comprising: forming a heat dissipating coating layer on the surface
of a heat dissipating layer; forming circuit patterns on the
surface of an insulating layer, and forming an inter-layer
conductive part joining with the insulating layer by passing
through the insulating layer and electrically connected with the
circuit patterns; and laminating the insulating layer on the heat
dissipating layer such that the inter-layer conductive part is
connected with the heat dissipating coating layer.
2. The method of claim 1, wherein the heat dissipating layer
comprises an Al substrate.
3. The method of claim 1, wherein the heat dissipating coating
layer comprises diamond-like carbon (DLC).
4. The method of claim 1, wherein the heat dissipating coating
layer is formed on both sides of the heat dissipating layer.
5. The method of claim 1, wherein the laminating comprises
laminating an additional insulating layer on the insulating layer,
and the additional insulating layer comprises an additional
inter-layer conductive part joining with the additional insulating
layer by passing through the additional insulating layer and
electrically connected with the circuit pattern.
6. The method of claim 5, further comprising interposing an
additional heat dissipating coating layer connected with the
additional inter-layer conductive part between the insulating layer
and the additional insulating layer before performing the
laminating of the additional insulating layer on the insulating
layer.
7. The method of claim 6, further comprising interposing an
additional heat dissipating layer between the insulating layer and
the additional insulating layer before interposing the additional
heat dissipating coating layer, wherein the additional heat
dissipating coating layer is formed on the surface of the
additional heat dissipating layer.
8. The method of claim 1, wherein the forming circuit patterns and
inter-layer conductive part comprises: forming a paste bump on a
metal layer and hardening the paste bump; laminating the insulating
layer on the metal layer such that the paste bump passes through
the insulating layer; and forming the circuit patterns by removing
a part of the metal layer.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a U.S. divisional application filed
under 37 CFR 1.53(b) claiming priority benefit of U.S. Ser. No.
11/812,661 filed in the United States on Jun. 20, 2007, which
claims earlier priority benefit to Korean Patent Application No.
10-2006-0055844 filed with the Korean Intellectual Property Office
on Jun. 21, 2006, the disclosures of which are incorporated herein
by reference.
BACKGROUND
[0002] 1. Field
[0003] The present invention relates to a printed circuit board and
a method for manufacturing thereof.
[0004] 2. Description of the Related Art
[0005] Presently, as electronic products are becoming thinner and
given more functionalities, a greater number of passive elements
and higher density and multi layer packages are being mounted in a
printed circuit board (PCB). This trend is expected to continue in
the future. On a basic level, the printed circuit board has
performed the role of connecting various kinds of electronic
elements or supporting components according to the design of
circuit patterns. However, as the number of passive elements and
packages mounted in the PCB is increased, so also are the amount of
power consumption and the amount of heat generated, whereby the
efficiency of heat dissipation is becoming an important decision
criterion in terms of reliability and consumer preferences. Thus,
there is a demand for a functional printed circuit board which can
effectively dissipate the heat generated due to the increased
functionalities.
[0006] A heat dissipating PCB refers to a functional PCB that
lowers the temperature of the whole PCB by having a part exposed to
the air or by spreading the heat generated in high density parts to
the other parts.
[0007] A conventional heat dissipating PCB is made by inserting one
or more metal layers in-between several layers or by adding a thick
metal layer onto the inner layer (core) part, etc. In the heat
dissipating PCB thus configured, the joining is performed using
Prepreg (FR-4 epoxy resin), an electrical conductive adhesive (ECA)
and/or an insulating resin, etc.
[0008] However, since the Prepreg, the electrical Conductive
Adhesive, and the insulating resin are made of polymer materials,
there is difficulty in effectively transferring heat to the heat
dissipating layer. Consequently, there is a problem of low
efficiency in heat dissipation.
SUMMARY
[0009] An aspect of the present invention is to provide a printed
circuit board (PCB) with high efficiency of heat dissipation and a
method for manufacturing the printed circuit board by delivering
the heat held in an insulating layer to a heat dissipating layer by
forming a heat dissipating coating layer with high thermal
conductivity on a heat dissipating layer.
[0010] One aspect of the invention provides a printed circuit board
that includes an insulating layer, a circuit pattern formed on one
side of the insulating layer, an inter-layer conductive part which
joins with the insulating layer by passing through the insulating
layer and which is electrically connected to the circuit pattern, a
heat dissipating layer laminated on the other side of the
insulating layer; and a heat dissipating coating layer which is
interposed between the insulating layer and the heat dissipating
layer and is connected with the inter-layer conductive part.
[0011] The heat dissipating layer may include an Al substrate, and
the heat dissipating coating layer may include one or more material
selected from a group consisting of gold, silver, and diamond-like
carbon (DLC). Also, the heat dissipating coating layer may be
coated on both sides of the heat dissipating layer.
[0012] Meanwhile, the printed circuit board may further include an
additional insulating layer, an additional inter-layer conductive
part which joins with the additional insulating layer by passing
through the additional insulating layer and which is electrically
connected to the circuit pattern, an additional heat dissipating
coating layer which is interposed between the insulating layer and
the additional insulating layer and which is connected with the
additional inter-layer conductive part.
[0013] The additional heat dissipating coating layer may include
one or more material selected from a group consisting of gold,
silver, and diamond-like carbon (DLC), and the printed circuit
board may further include an additional heat dissipating layer
interposed between the insulating layer and the additional
insulating layer.
[0014] The additional heat dissipating layer may include an Al
substrate, and the additional heat dissipating coating layer may be
coated on both sides of the additional heat dissipating layer.
[0015] The inter-layer conductive part may include paste bumps that
are connected with the circuit patterns and hardened.
[0016] Meanwhile, another aspect of the invention provides a method
of manufacturing a printed circuit board that includes forming a
heat dissipating coating layer on the surface of a heat dissipating
layer, forming circuit patterns on the surface of an insulating
layer and forming an inter-layer conductive part which joins with
the insulating layer by passing through the insulating layer and
which is electrically connected with the circuit patterns, and
laminating the insulating layer on the heat dissipating layer such
that the inter-layer conductive part is connected with the heat
dissipating coating layer.
[0017] The heat dissipating layer may include an Al substrate, and
the heat dissipating coating layer may include one or more material
selected from a group consisting of gold, silver, and diamond-like
carbon (DLC). Also, the heat dissipating coating layer may be
formed on both sides of the heat dissipating layer.
[0018] The laminating may include laminating an additional
insulating layer on the insulating layer, and the additional
insulating layer may include an additional inter-layer conductive
part which joins with the additional insulating layer by passing
through the additional insulating layer and which is electrically
connected with the circuit pattern.
[0019] The method may further include interposing an additional
heat dissipating coating layer connected with the additional
inter-layer conductive part between the insulating layer and the
additional insulating layer, before performing the laminating of
the additional insulating layer on the insulating layer.
[0020] Also, the method may further include interposing an
additional heat dissipating layer between the insulating layer and
the additional insulating layer, before interposing the additional
heat dissipating coating layer, where the additional heat
dissipating coating layer may be formed on the surface of the
additional heat dissipating layer.
[0021] Meanwhile, the forming of the circuit patterns and the
inter-layer conductive part may include forming a paste bump on a
metal layer and hardening the paste bump, laminating the insulating
layer on the metal layer such that the paste bump passes through
the insulating layer, and forming the circuit patterns by removing
a part of the metal layer.
[0022] Additional aspects and advantages of the present invention
will become apparent and more readily appreciated from the
following description, including the appended drawings and claims,
or may be learned by practice of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] FIG. 1 is a cross-sectional view showing a printed circuit
board according to an embodiment of the present invention.
[0024] FIG. 2 is a cross-sectional view showing a printed circuit
board according to a second disclosed embodiment of the present
invention.
[0025] FIG. 3 is a flowchart showing a method for manufacturing a
printed circuit board according to an embodiment of the present
invention.
DESCRIPTION OF EMBODIMENTS
[0026] Embodiments of the printed circuit board according to the
invention will be described below in more detail with reference to
the accompanying drawings. In the description with reference to the
accompanying drawings, those components are rendered the same
reference number that are the same or are in correspondence,
regardless of the figure number, and redundant explanations are
omitted.
[0027] FIG. 1 is a cross-sectional view showing a printed circuit
board according to an embodiment of the present invention, and FIG.
2 is a cross-sectional view showing a printed circuit board
according to a second disclosed embodiment of the present
invention. Referring to FIGS. 1 and 2, insulating layers 10,
circuit patterns 12, bumps 14, a heat dissipating layer 20 and heat
dissipating coating layers 30 are illustrated.
[0028] The insulating layers 10 may be made of Prepreg (PPG). The
circuit patterns 12 and the bumps 14 may be formed in the
insulating layer 10.
[0029] While Prepreg is presented as a material for the insulating
layer 10 in the present embodiment, other materials may also be
used, such as electro conductive adhesive and insulating resin,
etc., according to design requirements.
[0030] The circuit patterns 12 may be formed on one side of an
insulating layer 10. The circuit patterns 12 may be formed by
printing circuit patterns on a carrier film and transferring it to
the insulating layer 10. Also, the circuit patterns 12 may be
formed by exposing and etching. As such, the circuit patterns 12
may be formed by a variety of methods. Meanwhile, the circuit
patterns 12 serve as pathways through which electric signals may
move, and the circuit patterns 12 may be made of conductive
materials such as copper and silver. Of course, it is apparent that
the circuit patterns 12 may be made of conductive paste other than
that of copper or silver. The bumps 14 may be formed in
predetermined positions of the circuit patterns 12.
[0031] A bump 14 may be formed in a predetermined position of the
circuit patterns 12, and the position may be determined by the
design according to the function of the printed circuit board. The
bump 14 may be made of a conductive material such as copper and
silver.
[0032] The bump 14 may be formed to pass through the insulating
layer 10 in a direction along the plane of the insulating layer 10.
The bump 14 may pass through the insulating layer 10 by forming the
bump 14 on a carrier film together with the circuit patterns,
stacking the carrier film on the insulating layer 10, and then
pressing and transferring the bumps 14 from the carrier film to the
insulating layer 10. Of course, various methods may be used for
this, according to design requirements.
[0033] The bumps 14 may be connected to the circuit patterns 12 by
passing through the insulating layer 10. The bumps 14 may serve as
an inter-layer conductive part for connecting each layer
electrically. In this way, a multi-layer printed circuit board may
be formed.
[0034] While the bumps 14 made of conductive materials are
presented as an inter-layer conductive part in this embodiment,
other methods may also be used, such as using via-holes with
conductive material coated on the inner wall of the via-holes. As
such, the inter-layer conductive part may be formed by a variety of
methods.
[0035] The heat dissipating layer 20 may perform a function of
lowering the temperature of the PCB by holding the heat generated
in the PCB and emitting the heat to the air or by delivering the
heat to other parts of the PCB. The heat dissipating layer 20 may
be made of materials high in thermal conductivity, such as aluminum
(Al).
[0036] Meanwhile, the heat dissipating layer 20 may be selectively
interposed between a plurality of insulating layers and may be
stacked in order to improve the efficiency of the heat
dissipation.
[0037] Greater thickness in the heat dissipating layer 20 may be
advantageous, because the greater the thickness of the heat
dissipating layer 20, the greater the capacity for holding the heat
generated in the PCB. However, since the greater thickness of the
heat dissipating layer 20 may cause the PCB to be thicker as well,
the thickness of the insulating layers 10 may be reduced
correspondingly. Thus, the efficiency of heat dissipation may be
increased. The thickness of the heat dissipating layer 20 and the
corresponding thickness of the insulating layers 10 may be
determined according design requirements and conditions.
[0038] It may be expected that the efficiency of heat dissipation
is increased by forming the heat dissipating layer 20 inside the
PCB. However, because the basic component of Prepreg (FR-4 epoxy
resin), electrical conductive adhesive, and insulating resin, etc.,
used as the insulating layer 10 is polymer material, it may be hard
to deliver the heat to the heat dissipating layer 20. Thus, the
efficiency of heat dissipation may not be particularly high. To
improve this problem, the heat dissipating coating layers 30 may be
formed on the surfaces of the heat dissipating layer 20 to increase
the efficiency of heat dissipation.
[0039] The heat dissipating coating layer 30 may be interposed
between the heat dissipating layer 20 and the insulating layer 10
that has absorbed the heat generated inside the PCB, and the heat
dissipating coating layer 30 may improve the efficiency of heat
dissipation by facilitating the heat dissipation between the two.
Also, the heat dissipating coating layer 30 may be interposed
between insulating layers to connect with the inter-layer
conductive part. In this way, the heat dissipating coating layer 30
may facilitate the delivery of heat between insulating layers, and
improve the efficiency of heat dissipation.
[0040] The heat dissipating coating layer 30 may made of a material
including one or more material selected from a group consisting of
gold, silver, and diamond-like carbon (DLC), which provide high
thermal conductivity. Also, the heat dissipating coating layer 30
may be formed on one or both sides of the heat dissipating layer
20.
[0041] Meanwhile, the embodiments shown in FIGS. 1 and 2 are merely
examples of the invention, and the number of insulating layers 10
and heat dissipating layers 20, and the shape of the inter-layer
conductive part, etc., may be changed according to design
requirements.
[0042] Next, referring to FIG. 3, a method for manufacturing a PCB
according to another aspect of the invention will be described.
FIG. 3 is a flowchart showing a method for manufacturing a printed
circuit board according to an embodiment of the present
invention.
[0043] Operation s1 is that of forming the heat dissipating coating
layer 30 on the surface of the heat dissipating layer 20 before
stacking the heat dissipating layer 20 on the insulating layer 10.
For example, the heat dissipating coating layer 30 made of any one
of gold, silver, and DLC (diamond like carbon), or a combination
thereof, may be formed on both sides of the heat dissipating layer
20.
[0044] The heat dissipating coating layers 30 may be formed by a
variety of methods such as those using PECVD (Plasma Enhanced
Chemical Vapor Deposition), ion plating, laser ablation, and
filtered vacuum arc, etc.
[0045] Among the described methods, an illustrative method using
ion plating is as follows.
[0046] Ion plating is a method for obtaining a film having a
cohesive power higher than that from the general vacuum plating
method, by evaporating metal in a vacuum container and setting up a
cathode (-) on the substrate (base material) and accelerating the
ionization by means of glow discharge. Glow discharge is generally
used for the ionizing. During the ionizing, a great variety of
particles are generated. To improve the efficiency of the ion
plating, it is necessary to enhance the ionization ratio (the
proportion of the ionized atoms in the evaporated particle reaching
a substrate).
[0047] For a vacuum container filled with Ar gas with a pressure of
about 1.times.10.sup.-2.about.1.times.10.sup.-3 Torr, where a
negative (-) voltage of about -0.5.about.2 kV with respect to the
wall of the vacuum container is provided to the substrate, the glow
discharge may take place between the substrate and its
surroundings. Here, a strong dark space may be generated around the
substrate. In this state, if a metal (or compound) is evaporated
from an evaporation source, the evaporated atoms are ionized in the
plasma of the glow discharge. The ionized and evaporated atoms are
accelerated in the dark space with the gas ions, collide with the
substrate and are coated on it. This is the Mattox method, and its
ionization ratio is just 0.1.about.0.3%.
[0048] Therefore, many methods for increasing the ionization ratio
are presented, for example, {circle around (1)} the multi-cathode
method, in which a hot cathode is set up in proximity to the
substrate, so that the thermions generated collide with the
evaporated atoms, resulting in ionization, {circle around (2)} the
high-frequency wave excitation method, in which a high-frequency
coil is set up on the evaporation source to promote the ionization
by the high-frequency magnetic field, {circle around (3)} the
induction heating method, in which ionization is promoted by a
leakage flux as high frequencies are used to accelerate the
evaporation source, {circle around (4)} the activated reactive
evaporation (ARE) method, in which a gas that reacts easily with
the evaporated atoms is provided in the evaporation space, and a
stoichiometrically good compound is obtained by applying a
discharge to the reactive evaporation for covering the compound,
{circle around (5)} the cluster method, in which parts of a cluster
of evaporated atoms are ionized and made to collide with the
substrate, {circle around (6)} the hollow cathode discharge (HCD)
method, in which materials are evaporated with a plasma electron
beam using a special low-voltage high-current electron gun (HCD
electron gun) and ionized at the same time, and {circle around (7)}
the arc discharge method, in which the metal cooled by the arc
discharge using the metal of the evaporation material as a cathode
target is locally melted and simultaneously inonized.
[0049] As such, the ion plating as described in the above allows
close adhesion between the film and the substrate and good
compactness of the film. Also, special compound films may be
obtained such as TiN, TiC, CrN, CrC, Al.sub.2O.sub.3, and
SiO.sub.2, etc. In addition, the substrate may not be deformed
because the coating temperature is low.
[0050] Operation s2 is that of forming a circuit pattern and an
inter-layer conductive part in the insulating layer 10.
[0051] For example, the circuit pattern and the inter-layer
conductive part may be formed at the same time by forming
conductive paste bumps 14 on a copper foil, hardening them,
stacking the insulating layer 10 on the copper foil so that the
paste bumps 14 pass through the insulating layer 10, and then
removing parts of the copper foil.
[0052] Besides this, the inter-layer conductive part may be formed
by forming via holes passing through the insulating layer 10 and
then coating the inner wall of the via holes with conductive
material.
[0053] Operation s3 is that of stacking the insulating layers 10 on
the heat dissipating layer 20 to complete the manufacture of the
PCB.
[0054] The PCB may be formed by sequentially laminating the
insulating layers 10, which have the inter-layer conductive part
and the circuit patterns 12, on the heat dissipating layer 20,
which has the heat dissipating coating layer 30. Also, the PCB may
be formed by stacking them preliminarily and then laminating
collectively. The number of the insulating layers 10 and the number
of the heat dissipating layer 20 may be varied according to design
conditions and requirements.
[0055] By sequentially performing the operations s1 to s3, a PCB
having a high efficiency of heat dissipation may be
manufactured.
[0056] According to the present invention comprised as above, the
heat contained in the insulating layer 10 may effectively be
delivered to the heat dissipating layer 20 and the efficiency of
heat dissipation may be improved by forming the heat dissipating
coating layer 30 with high thermal conductivity on the heat
dissipating layer 20.
[0057] While the present invention has been described with
reference to particular embodiments, it is to be appreciated that
various changes and modifications may be made by those skilled in
the art without departing from the spirit and scope of the present
invention, as defined by the appended claims and their
equivalents.
* * * * *